In a semiconductor device handling analog signals, passive elements such as a capacitor, a resistor, and an inductor are important constituent elements for integrated circuits. Since such passive elements are difficult to be fabricated into a semiconductor chip, they have been mounted as external parts on a packaging substrate. However, since requirement for increasing the operation speed of a system and space saving have become increased in recent years, it has been attempted to incorporate passive elements into a semiconductor chip.
As a method of forming a resistor in the inside of a semiconductor chip, while several methods have been proposed, a method of fabricating a poly-silicon film formed by CVD (Chemical Vapor Deposition) method into a desired pattern and using the same as a resistor has been adopted generally. For example, JP-A-Sho 54(1979)-083786 discloses a method of forming a resistor using a poly-silicon film.
Further, a method of using a metal film capable of low temperature formation as a material for the resistor has been proposed. Generally, a metal film can provide a film of high quality also by using a sputtering method or a plasma CVD method at a low deposition temperature. Accordingly, since the resistor can be formed even after forming an interconnection using aluminum or copper, it is possible to provide a resistor with low parasitic capacitance and excellent high frequency property. For example, JP-A-Sho 56(1981)-064405, discloses a method of forming a resistor using a metal film.